U.S. Pat. Nos. 7,997,183 and 7,201,094 describe a firearm with a bolt mechanism that has a movement component perpendicular to the projectile barrel axis. Firearms manufactured according to the teachings of the aforementioned patents are commercialized under the trademarks KRISS Vector™ and Super V System™. The forementioned firearm has the particularity of redirecting the moving bolt from the firing axis to a downward direction thus reducing muzzle climb and recoil force. The redirection of bolt movement is obtained by means of V-shaped grooves provided in the internal surface of the opposed sidewalls of the bolt receiver assembly. The V-shaped grooves have a first portion parallel to the firing axis, and a second portion transverse to the firing axis. The unique configuration of this bolt movement mechanism has an influence on the rate of fire, which many users have felt to be too rapid. A rapid rate of fire may also decrease the reliability and constancy of cartridge ejection, especially in fully automatic mode of fire, but also in semi-automatic mode of fire.
The forementioned problems are not limited to KRISS type firearms and may also be found in firearms with linear bolt movement mechanisms.